Here’s some notes from my work on Sophia. Please note that if no video is showing it might be worth switching the NTSC / PAL switch to NTSC (OFF) as there were some issues from memory. Doesn’t mean much these days with TVs being 50 / 60Hz worldwide – Thanks globalisation!
Switch Bank 1
Switch Bank 2
Sophia shipped with 1×8MB RAM chip from factory.
Samsung KMM5362000B2G-7, access time 70ns.
A-Bus board is the top board with RAM slots. 32MB RAM maximum (4×8MB).
Cable running from Sophia A-Bus board to SH-2 CPU cards is a branched EVA board power cable.
What I haven’t been able to work out is the following:
What are the HCD63 markings on Sophia.
What is the EVA-PO-S / EVA-P0-S 4-pin header CN10 connector joins CN4 on SH-2 CPU Card.
171-6692B (ADK-7000) vs 171-6692D (HCD63) – Manufacturers perhaps?
Until we know, I guess we’ll never know.